<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>Tab栏切换</title>
        <link rel="stylesheet" href="tab.css">
       <style>
        * {
            margin: 0;
            padding: 0;
          }
          
          li {
            list-style-type: none;
          }
          
          .tab {
            width: 978px;
            margin: 20px auto;
          }
          
          .tab_list {
            height: 39px;
            border: 1px solid #ccc;
            background-color: #f1f1f1;
          }
          
          .tab_list li {
            float: left;
            height: 39px;
            line-height: 39px;
            padding: 0 20px;
            text-align: center;
            cursor: pointer;
          }
          
          .tab_list .current {
            background-color: #c81623;
            color: #fff;
          }
          
          .item_info {
            padding: 20px 0 0 20px;
          }
          
          .item {
            display: none;
          }
        </style>
    </head>
    <body>
        <div class="tab">
            <div class="tab_list">
                <ul>
                    <li class="current">商品介绍</li>
                    <li class="current">规格包装</li>
                    <li class="current">售后保障</li>
                    <li class="current">商品评价</li>
                    <li class="current">手机社区</li>
                </ul>
            </div>
            <div class="tab_con">
                <div class="item" style="display: block;">商品介绍模块内容</div>
                <div class="item" style="display: none;">规格与包装模块内容</div>
                <div class="item" style="display: none;">售后保障模块内容</div>
                <div class="item" style="display: none;">商品评价模块内容</div>
                <div class="item" style="display: none;">手机社区模块内容</div>
            </div>
        </div>
        <script>
            var numTest = 10;
            var lis =document.querySelectorAll('.tab_list li');
            var items =document.querySelectorAll('.item');
            for(var i=0;i<lis.length;i++){
                lis[i].setAttribute('index',i);
                lis[i].onclick = changeTab;
            }
            console.log('外层：'+ this);
            function test(){
                console.log('test:'+this);
            }
            window.test()
            function changeTab(){
                console.log(this);
                for (var j=0;j<lis.length;j++){
                    if(lis[j] !==this){
                        lis[j].className='';
                    }else{
                        this.className='current'
                    }
                }
                var index = this.getAttribute('index');
                for(var i=0;i<items.length;i++){
                    if(items[i]!==items[index]){
                        items[i].style.display='none';
                    }else{
                        items[index].style.display='block';
                    }
                }
            }


        </script>
    </body>
</html>